1. Plan : intro Characterization of thin films and bulk materials using x-ray and electron scattering V. Pierron-Bohnes IPCMS-GEMME, BP 43, 23 rue du Loess, 67034 Strasbourg Cedex 2 electronic properties magnetism, optics, transport… structural properties preparation conditions small dimensions Research topics: - superalloys NiAl, FeAl, (Co,Fe,Mn)Pt 3 (order – kinetics – magnetism) - multilayers Co/Mn, Co/Ru (stucture – magnetism) - anisotropic alloy thin films (MBE, sputtering) CoRu, CoPt, FePt, NiPt -(structure – magnetism – interdiffusion)

2. Plan : interactions Characterization of thin films and bulk materials using x-ray and electron scattering V. Pierron-Bohnes IPCMS-GEMME, BP 43, 23 rue du Loess, 67034 Strasbourg Cedex 2 1) electron and x-ray interaction with matter 2) real lattice and reciprocal lattice in 3D and 2D samples 3) experimental set-ups 4) studies on single crystals 5) synchrotron radiation 6) strains measurements using x-ray scattering and TEM 7) powder scattering measurement 8) texture analysis 9) reflectometry 10) chemical analysis 11) short and long range order measurements

3. electron-matter interaction 1 An electron has: - a mass: 9.1 x 10 -31 kg - a charge 1.6 x 10 -19 C to interact with other electrons and nuclei in V 511 kV V acc =100kV =0.0037 nm

4. electron-matter interaction 2 Electronic structure of atoms

5. electron-matter interaction 3 energy loss electron Incident electron secondary electron (E < 50eV) Transmitted beam with energy loss

6. electron- matter interaction 4 primary electron energy loss electron incident electron Emission of a primary electron Inelastically scattered electron

7. electron- matter interaction 5 Auger electron energy loss electron photon wavelength intensity dis-excitation

8. electron- matter interaction 6 secondary electron (E < 50eV) Emission of a secondary electron

9. x-ray interaction with matter Incident x-ray beam E = h 0 Rayleigh + Thomson diffusion (coherent + elastic) E ≈ h 0 Compton diffusion (incoherent + slightly inelastic) E ≠ h 0 Absorption + reemission: fluorescence… (incoherent + strongly inelastic) E = h 0 X-rays: no mass, no charge → interaction as the effect of electro-magnetic field on charges electrons (photoelectric effect)

10. Thomson small large h 0 x-ray- matter interaction Incident x-ray beam E = h 0 Rayleigh + Thomson diffusion (coherent + elastic) E = h 0 Rayleigh large small h 0

11. x-ray- matter interaction Incident x-ray beam E = h 0 E ≈ h 0 Compton diffusion (incoherent + slightly inelastic) nucleus hole Photon: particle with E = h and p = hc/ = with

12. x-ray- matter interaction Incident x-ray beam E = h 0 Compton diffusion (incoherent + slightly inelastic) E << h 0 Absorption + reemission: fluorescence… (incoherent + strongly inelastic) excited electron incident photon emitted photon

13. Incident x-ray beam E = h 0 photoelectric effect e-e- nucleus hole Energy probabilty x-ray- matter interaction

14. x-ray interaction with matter Incident x-ray beam E = h 0 Rayleigh + Thomson diffusion (coherent + elastic) E ≈ h 0 Compton diffusion (incoherent + slightly inelastic) E ≠ h 0 Absorption + reemission: fluorescence… (incoherent + strongly inelastic) E = h 0 electrons (photoelectric effect) Hard x-rays : within 0.01 – 0.1nm Soft x-rays: within 0.1 – 0.25 nm

15. x-ray diffusion by one electron electron acceleration field emitted in direction k  =  /2 angle between k and   E E 2 per solid angle

16. x-ray diffusion by one atom Electronic distribution electronic states atomic volume Contribution of extended states Contribution of localized states Interference effects (diffusion factor) Hartree-Fock calculations: F

17. dependent on the energy only dependent on the direction only diffusion factor at absorption edge absorption edge energy anomal diffraction: enhanced contrast at the edge of the light element Mn edge Cromer –Liberman method

18. Relations between , f’ and f’’ Kramers- Kronig relations f’ and f” obey the Kramers- Kronig relations Absorption: the intensity decreases as exp(-  z) Maxwell equations If  is complex, k is complex because  or  : in the international tables of crystallography x-rays pass through some  m atomic volume

19. Sasaki tables

20. Co edge

22. electron diffusion by one atom The deviation of the electron is due to their electrostatic interaction because the mechanical interaction (collision) has a too small probability The elastic part is due to the deviation by the electric potential due to both nuclei and electrons, but the nuclei is predominant. ≈ Q -2

23. compared diffusion amplitudes

24. compare scattering amplitudes and atomic scattering factors for x- rays, electrons and neutrons comparison of the thickness to absorb 99% of the beam for different rays absorption